vim import java.util.*;
public class Factorial {
  public static void main (String arges[])
    for(String arg :args)
      int i=integer.parseInt(args[i]);
         n=i;
      System.out.println(fact(n));
  }
  public static int fact(int n){
    if (n==0)
      return 1;
    else
      return n*fact(n-1);
  }
}
